Website Analytics - Tracking and Logging Forum

I've been playing around with useragent string lately, because it seems to be the way of detecting user's browser/OS... but it can be very unreliable, as these can be changed very easily with modern web browsers.

But if you look at web sites like www.mozilla.com/firefox, it seems like they are not using the useragent string for OS detection! Today I have modify my useragent string to a non-existing OS and browser, and mozilla.com is still be to detect my real OS!

So I am wondering how did they do that? Is there some other techniques for OS detection? They are not using OS fingerprinting are they?

Capabilities are far harder to spoof. A simple test is to check if various javascript objects or methods known to only be supported in certain browsers or operating system implementations of those browsers exists.

It depend on what information the browser shows to javascript. Their method is also pretty basic.

On the same front you have browser detection. I've seen most sites, even google, using basic detection that can be spoofed easily by simply changing the user-agent. In fact there are alternative methods to better detect the type of browser. So far, the code I use hasn't reported false positives (100% reliable for FF, IE, Op). I'm sure a solid method can also be devised for OS detection.